The number of people approved to use medical marijuana in Illinois remains too low to sustain the industry, business owners said.

Only about 100 more patients have been cleared in the past month to access medical pot, raising the statewide total to about 2,600, the Illinois Department of Public Health reported Wednesday.

About 22,600 people have signed up on the state’s website to obtain medical marijuana, but only 3,200 have completed the application. The state law requires patients to submit fingerprints for criminal background checks and to get a doctor’s recommendation, which some patients say has been difficult.

The low number of approved users remains the greatest concern for growers and dispensary owners, said Joseph Friedman, who plans to open a dispensary in Buffalo Grove and is a board member of the Medical Cannabis Alliance of Illinois, a trade group that represents some of the state’s license holders.